I. Field
The following description relates generally to wireless communications, and more particularly to providing multiple multi-sector broadcast paging channels to provide region-wide paging of wireless devices with improve spectral efficiency.
II. Background
Orthogonal Frequency Division Modulation or Orthogonal Frequency Division Multiplexing (OFDM) is a protocol that is currently utilized in wireless environments to transmit and receive data. OFDM modulates digital information onto an analog carrier electromagnetic signal, and is utilized in an IEEE 802.11a/g WLAN standard. An OFDM base band signal (e.g., a subband) is a sum of a number of orthogonal sub-carriers, where each sub-carrier is independently modulated by its own data. Benefits of OFDM over other conventional wireless communication protocols include ease of filtering noise, ability to vary upstream and downstream speeds (which can be accomplished by way of allocating more or fewer carriers for each purpose), ability to mitigate effects of frequency-selective fading, etc.
Paging channels are employed in wireless networks to page a mobile device, such as a cellular phone, in order to instruct the mobile device to connect to the network for service. In conventional systems, the network has only a rough knowledge of a location of a mobile device, and no knowledge of channel quality in the area of the mobile device prior to page transmission. Consequently, a page message typically must be sent over a wide region (e.g., a plurality of sectors) at low spectral efficiency due to such inadequate information. Thus, typical paging systems employ a paging channel that is transmitted independently from each sector in a paging region, which can be established based on a registration history for the mobile device. A page can then be transmitted to the mobile device by sending the paging message from each sector in the region. While such paging message can be transmitted at approximately the same time, page transmissions are typically independent of each other.
Some conventional systems employ what is known as a forward link soft-handoff to improve performance. This technique permits multiple sectors to transmit a paging signal to a mobile device when the network has an estimate of the location of the device. However, even though sectors can transmit the same signal, such signals are subject to sector-specific scrambling, which in turn requires that the mobile device receive and decode the signals separately, and combine signal energy at the receiver after receipt and separate decoding. Such systems unnecessarily increase device complexity and signal translation overhead while reducing spectral efficiency.
In view of at least the above, there exists a need in the art for a system and/or methodology that facilitates improving paging signal spectral efficiency within a transmission sector, and in particular near sector boundaries.